Three Dice
This is a great way to break up the monotony of classes. Great for all levels.
Materials: Three dice and a cup. Directions: Put the three dice in a cup and shake it up. When the dice settle, add the sum of the dice together (if the dice say 3, 5, and 1, then the sum is 9).
Then, start with one student and go around the room. The students have to count, starting with "one," until one of the students says the "sum" of the dice. Each student can say one, two, or three numbers. (The first student might say "1, 2." The second student could say "3, 4, 5." The third student might say "6." The fourth student could then say "7, 8." The next student would say "9." This student loses, because 9 is the sum of the dice.
By the way, this game only works if the students are unaware of the sum of the dice in the cup. It keeps them guessing and creates suspense.
The student who says the "sum" of the dice must perform the task that you determine. I often use this game in the most mundane of ways: when we're doing our reading book or magazine, instead of just taking turns reading, I use this "game" to determine who the next reader will be. Or you can make the "loser" say a sentence with a vocabulary word, or ask a question, or review whatever aspect you are currently teaching.
Always keep a cup and three dice on your desk, just in case.

ESL Activity: The Lying Game!
More great games like this in our ESL games book: The Great ESL Games Compendium!
Materials: pen, paper. Directions: First, you, the teacher, write down three things about yourself, two of which are lies. (For example: a) I have been to Japan b) I have eaten a snail c) I have ridden a horse.) Read them to the students, who then write down a, b, or c, to guess which statement is true. After everyone has guessed, reveal the true answer, and give each student who guessed correctly one point. (If no one guesses the correct answer, award the liar one or two points!) Then, everyone has 5 minutes or so to write down three things about themselves, of which two must be lies. Have the first student read his/hers, and have everyone guess which one is true, assigning points for correct guesses as before. Then go on to the next student, and proceed until everyone has read their three statements. Students tend to really enjoy this game. I usually buy a tea or give a prize to the student or students who have the most points at the end.
To make this game much more interesting, after the student has read the 3 sentences about him/herself, allow anyone to ask that person one question (or more, if you like). This way, the student must actually try to lie convincingly, and the game lives up to its name!

The Symbol Game
By the end of this game, everyone should have a smile on their faces and be familiar with all of their classmates.
Directions: This can be used for students of all ages. Have each of the students introduce themselves and choose an object or word to be their symbol. (For example, I could say, “Brian” and “orange” because my favorite color is orange.) After everyone has introduced him/herself, including the teacher, say someone’s symbol. That person must then say another person’s symbol, and so on. If someone hesitates or says the wrong symbol, they are out. (For a “punishment,” you could have them try to say everyone’s name, or symbol.) 
Cardhead  Speaking Game
This is a good, simple game for intermediate and advanced students that gets them talking and having a bit of fun.
Materials: pen, small rectangular pieces of paper (about the size of playing card) Directions: Have the students sit in something resembling a circle. Hand out one square of paper to each student. Tell them to write the name of a famous person on the paper, but not to let anyone else see it. The name should be of a person that everyone in the class will know! When they finish writing, they should turn over their piece of paper. When everyone is finished, have them pass their papers clockwise (or counterclockwise), and on the count of three, the students hold the piece of paper up to their forehead so that everyone else can see it  but each student cannot see the name on his/her piece of paper. Students take turns asking their classmates Yes/No questions to try to figure out the name on their cards. When students guess correctly, they can put down their piece of paper and take their hands down from their forehead. (This tends to be reward enough, as they feel quite silly holding a piece of paper up to their forehead...) For a variation on this game, instead of writing the name of a famous person on the cards, you can choose any category for the students. For example, they can write their favorite food, or an animal, or things you can buy in a convenience store, etc. 
Murder Winks
A classic party game that is easily adapted to the classroom.
Directions: The students stand in a circle, and one of them will be the "murderer". This student will "murder" other students by winking at them. To choose the murderer, you can either a) have them close their eyes, walk around the circle, tapping one student on the back, or b) put one square of paper for each student in a hat, writing "murderer" on one piece and "innocent" on all the others; the students silently choose a piece of paper to determine who is the murderer. Now the game begins. If the murderer "winks" at a student who is looking back at him/her, then the student is "dead" and must sit down. (The "dead" student can exaggerate his/her death, but must not reveal who the murderer is.) The murderer tries to "kill" as many people as possible in this way, without anyone else discovering who the murderer is. If someone correctly guesses who the murderer is, the game is over and that person "saves" everyone who is still "alive". However, if someone guesses incorrectly, then he/she is "dead" too, and must sit down. As more and more people "die" and the group gets smaller, it gets very difficult to be the murderer without getting caught. You can therefore set a limit  say, 4 or 5 murders  after which the murderer is the winner. Students will want to play this game over and over. It's good to introduce after teaching the words "murder" or "innocent". Otherwide, there's not a lot of educational value to this game, but it's a good icebreaker or a good way to break up a class, and if nothing else, the students will learn how to wink! 